SpringBoot Tomcat warns about a missing +/- prefix when enabling multiple protocols through server.ssl.enabled-protocols

When configuring SSL with Tomcat, the following message is being logged in warning level by SSLHostConfig:

"The protocol [{0}] was added to the list of protocols on the SSLHostConfig named [{1}]. Check if a +/- prefix is missing."

This is because Tomcat's SSLHostConfig semantics for protocol string is:

        // List of protocol names, separated by ",", "+" or "-".
        // Semantics is adding ("+") or removing ("-") from left
        // to right, starting with an empty protocol set.
        // Tokens are individual protocol names or "all" for a
        // default set of supported protocols.
        // Separator "," is only kept for compatibility and has the
        // same semantics as "+", except that it warns about a potentially
        // missing "+" or "-".

Comment From: mhalbritter

Thank you very much and congratulations on your first contribution :tada:!